adjust the realism of velocity

Hi, the problem that´s occur it´s the frames, the velocity don´t match with the reallity, in the game payback, the realism it´s amazing, the frames the scenario pass by so quickly, you are imerse in the real situation, I beg you please fix up the realism of the frames to pass by more rapid, and the cars slize so much too, soo much instability, thanks for all